Kinetic study on the reaction of polyvinyl chloride thermal dehydrochlorination

Abstract

The kinetics of the thermal dehydrochlorination of polyvinyl chloride have been studied in the temperature range 180 "C.-25OoC. in inert and oxygen-containing atmosphere. The effect of the molecular weight of the polymer on the dehydrochlorination rate is shown. When the thermal degradation occours in presence of oxygen the reaction becomes autocatalytic and the activation energy for dehydrochlorination is strongly lowered (from 33 to 24 Kcal/mole). The literature on the thermal polyvinyl chloride degradation is reviewed and experimental results are discussed and interpreted. Z U S AMME N F AS S UNG:Es wurde die Kinetik der thermischen Zersetzung von Polyvinylchlorid bei 180°C. bis 250°C im Stickstoff-und Sauerstoff-Shom an einheitlichen Fraktionen untersucht. Es wird der EinfluD des Molekulargewichts auf die Geschwindigkeit der HCLAbspaltung beschrieben. In Anwesenheit von Sauerstoff ist die Zersetzungsreaktion autokatalytisch und die Aktivierungsenergie stark erniedrigt. Nach einem AbriD der neueren Literatur wird ein Mechanismus fiir die HC1-Abspaltung in Stickstoff-Atmosphare vorgeschlagen.

The thermal degradation of polyvinylchloride in solution. I. The kinetics of the dehydrochlorination reaction

“…The value of the overall energy of activation for the dehydrochlorination reaction is rather lower than the 26-39 kcal./mole values of previous investigators6,10a12 14). It is surprisingly close to the value of 22.5 kcal./mole obtained by BAUM and WARTMAN4) for the dehydrochlorination of 4 chloro-2-hexene.…”

TG-FTIR analysis of PVC thermal degradation and HCl removal

“…In most of the early experiments, dehydrochlorination was studied mainly with the aim of improving the thermal stability of PVC [4]. Then the kinetics of the thermal decomposition of PVC was studied [5,6], and the conversions of PVC into liquid products and solid materials were reported [7,8]. Toxic chlorine compounds, such as PCDD and PCDF, were detected in fly ash discharged from waste incineration plants.…”

Sur la déagradation thermique du chlorure de polyvinyle. II. Etudes cinéatiques sous atmosphéare inerte

“…11 Le present travail a pour but de preciser, dans la mesure du possible, et par Btude cinbtique, les causes et les mecanismes de la degradation thermique du chlorure de polyvinyle (CPV). La complexite des phdnomenes impliques a conduit les aut,eurs B operer dans les conditions experimentales les plus simples: sous atmosphere inerte d'azote purifi6 et avec un produit commercial debarass6 au maximum des impuretes qu'il pouvait contenir.…”